Denture casting flask



Oct. 28, 1941. N, AY 2,260,909]

DENTURE CASTING FLASK Filed April 23, 1940 ATTORNEY.

Patented Oct. 28, 1941 UNITED STATES PATENT OFFICE DENTURE CASTING ELASK Nathan Kaye, New York, N. Y.

Application April 23, 1940, Serial'No. 331,087

3 Claims.

This invention relates to instrumental-ities used in the practice of dentistry and more particularly to appliances for the production of metallic 'test casts from wax impressions of the gums in a body of investment during the process of preparing a denture plate.

The customary practice has been; to use the wax impression of "the gums, as a template or pattern, to form a mold in investment material, such as plaster of Paris, set hydrolitically, into which, after drying and hardening, the molten metal, as gold, is poured forming a cast, which, after trimming and polishing, presumably fits the mouth .and gums.

It is found in practice that such casts for the edentelous patients particularly those wearing lower plates seldom fit with the requisite degree of accuracy, requiring refitting and frequently reshaping or recasting, before becoming satisfactory, all of which is expensive and consumes both the practitioners and patients time and patience. Therefore, an object of the present invention is to provide a method and means to obviate such difiiculty by an intermediary step that includes the use of a test cast, easily and quickly made of inexpensive material, readily amenable to reforming, cutting, bending and otherwise shaping to an exact fit of the gums, and which, in its perfected condition, is used as a pattern for the final cast- A further feature is in the provisicnof'a sectional flask for such trial cast, that is easy to operate in preparing, pouring and removal of contents, and which may also be used in making the plate cast in its final correct condition.

Another purpose is to produce a simple sectional flask in which certain sections are expansible after release, separating from the mold material automatically, and having means for adjusting and retaining the block of investment material when completed.

These and other advantageous aims, which will later appear, are accomplished by the novel and practical construction, combination and arrangement of parts hereinafter described and shown in the accompanying drawing, constituting an essential component of this disclosure, and in which:

Fig. 1 is a partial side elevational, partial sectional view of an embodiment of the invention,

Fig. 2 is a top plan view thereof, and

Fig. 3 is a perspective View of one of the expansible ring elements.

Referring in greater detail to the drawing, the

uniform with the ring 2|.

i5, is here shown as a rigid circular plate, with or without a thin elevating ring l t at its lower margin, and having on its upper level surface a circumamb'ient raised flange H; the inner face '21, which may be of any desired height and of uniform thickness, this ring having at its upper end a similar bevelled edge 22 "both edges 20 and 22ersreduced in thickness .at their outer sides from the main body of the ring, but uniiorm and level with its inner surface.

On the outer-surface of "the ring 21 are a-series of pads 23 in which are fitted radial adjusting screws '24 for a purpose further on apparent.

The characteristic feature of the ring 2| is its diametral expansibility, obtained by reason of a transverse slit 25, extending from one extreme edge to the other and preferably formed tangentially to the axis of the ring.

Due to the inherent elasticity of the ring material the ends of the ring at the out are normally spaced apart, see Fig. 3, but when set in the base flange the ends are held in close contact.

Another similar ring 21 is shown as superposed on the ring 21, its lower edge 28 engaging over the corresponding edge 22 and its inner surface The upper edge 29 of the ring 21 is substantially similar to the edge 22 of the lower ring and like it has a transverse slit 3|].

A cover 32 has a down-reaching marginal flange 33 below its beaded edge 34, the flange adapted to engage over the edge 29 of the upper ring or over the edge 22 of the lower ring, in case the upper ring is not usd.

The closure 32 preferably has a central aper- 0 ture 35 of considerable size and spaced circumjacent is a circular channel 36, in the bottom of which are a series of pouring openings or vents 31 extending downwardly and towards the axis of the apparatus.

In order to facilitate raising the cover an eccentric or cam is recessed into the wall of the ring 21 and rotatably mounted on a stem 4|, held by a flanged head in the ring, the eccentric being provided with an outwardly extending, lever-like handle 42 for manual actuation.

In operation, a replica of a patients gum is produced by the usual means of bite taking upon a mass of impression material in a plastic condition; after hardening the impression material base of the apparatus, designated by the numeral 55) a plaster cast is made from it, the mold 5|,

which, for a full denture restoration, is generally horse-shoe shaped in plan (see Fig. 2).

This investment material in the form of a block, preferably circular, is placed on the upper surface of the base l5, adjusted substantially central and held by the screws 24 in the ring 21, now contracted by being seated within the flange ll, after which the remaining space is filled with a plastic substance 52, all being essentially level with the upper edge of the ring.

The ring 21, if to be used, is then positioned on the lower ring and the cover applied, other plastic material 53 being entered through the aperture 35; passages 54 are formed leading from the openings 31 to the mold 5| and a metal of low melting point, approximately 235 degrees, in a fluid molten condition poured into the channel 36, flowing through the openings 31 and passages 54 to fill the mold, the sprues remaining in the passages. Suitable funnels (not shown) may be placed in the passages 54 through which the molten metal will pass into the mold 5|.

When the metal has solidified by cooling, the cover is raised, assisted by the cam or eccentric 40, the ring 21 springing open freeing its contents, and allowing the lower ring 2| to spread, releasing the cast, which is cleaned, the sprues removed, and the cast smoothed for trial insertion in the mouth.

Obviously, when the cast has been accurately fitted to the gums, it provides a pattern which is an exact replica of the desired restoration and is to be used as a pattern for the final cast.

Although the foregoing is descriptive of the best known embodiment of the invention, it is to be regarded as suggestive rather than restrictive, as obviously many modifications and changes may be made within the scope and spirit of the subjoined claims.

Having thus described this invention, including its construction and application, what is claimed as new and sought to secure by Letters Patent, is:

1. A denture casting flask comprising a circular base having a raised marginal flange, a ring engageable within said flange, a second ring interfitting the first ring, both rings being split parallel to their axes, adjusting means disposed radially in said first ring, a closure cover engageable on the rim of the second ring, said cover having an annular channel interjacent its margin, and a series of pouring passages open to the recess directed angularly to the axis of said base.

2. A denture casting flask comprising a base having a raised marginal flange, an expansible ring having tapered upper and lower edges, said lower edge resting on said base within said flange, a rigid cover having a down-reaching flange engageable with the upper edge of said ring, means carried by said ring to adjust a matrix disposed on said base, and means in said cover to facilitate pouring melted material into the matrix.

3. A denture casting flask comprising a base having a raised marginal flange, a transversely split ring to seat on said base within said flange, a closure plate having a down-reaching annular flange to engage over the opposite end of said ring, the flanges of said plate and base confining the ends of said ring in juxtaposition, and means to manually release said closure from the ring.

NATHAN KAYE. 

